CN113351612A - System and method for treating fly ash by water washing and desalting combined with high-temperature melting - Google Patents
System and method for treating fly ash by water washing and desalting combined with high-temperature melting Download PDFInfo
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- 239000010881 fly ash Substances 0.000 title claims abstract description 235
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 130
- 238000005406 washing Methods 0.000 title claims abstract description 106
- 238000002844 melting Methods 0.000 title claims abstract description 98
- 230000008018 melting Effects 0.000 title claims abstract description 98
- 238000000034 method Methods 0.000 title claims abstract description 64
- 238000011033 desalting Methods 0.000 title claims abstract description 16
- 238000010828 elution Methods 0.000 claims abstract description 88
- 239000003480 eluent Substances 0.000 claims abstract description 86
- 239000002956 ash Substances 0.000 claims abstract description 61
- 238000001035 drying Methods 0.000 claims abstract description 56
- 238000001704 evaporation Methods 0.000 claims abstract description 47
- 230000008020 evaporation Effects 0.000 claims abstract description 46
- 150000003839 salts Chemical class 0.000 claims abstract description 41
- 238000000746 purification Methods 0.000 claims abstract description 37
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 22
- 239000003546 flue gas Substances 0.000 claims abstract description 22
- 239000007788 liquid Substances 0.000 claims description 78
- 229910001385 heavy metal Inorganic materials 0.000 claims description 44
- 239000012452 mother liquor Substances 0.000 claims description 39
- 230000008569 process Effects 0.000 claims description 30
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 24
- 239000011591 potassium Substances 0.000 claims description 24
- 229910052700 potassium Inorganic materials 0.000 claims description 24
- 239000002244 precipitate Substances 0.000 claims description 24
- 238000001914 filtration Methods 0.000 claims description 22
- 239000011552 falling film Substances 0.000 claims description 21
- 238000010612 desalination reaction Methods 0.000 claims description 19
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 claims description 19
- 238000000926 separation method Methods 0.000 claims description 19
- 238000001556 precipitation Methods 0.000 claims description 18
- 238000002425 crystallisation Methods 0.000 claims description 17
- 230000008025 crystallization Effects 0.000 claims description 17
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 14
- 210000003298 dental enamel Anatomy 0.000 claims description 14
- 239000011734 sodium Substances 0.000 claims description 14
- 229910052708 sodium Inorganic materials 0.000 claims description 14
- 159000000000 sodium salts Chemical class 0.000 claims description 14
- 238000006298 dechlorination reaction Methods 0.000 claims description 13
- 239000002562 thickening agent Substances 0.000 claims description 12
- 239000002002 slurry Substances 0.000 claims description 11
- 239000002918 waste heat Substances 0.000 claims description 9
- 239000012670 alkaline solution Substances 0.000 claims description 5
- 239000012153 distilled water Substances 0.000 claims description 5
- 238000009826 distribution Methods 0.000 claims description 4
- 239000007789 gas Substances 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 4
- 238000002360 preparation method Methods 0.000 claims description 4
- 238000009287 sand filtration Methods 0.000 claims description 4
- 239000011343 solid material Substances 0.000 claims description 4
- 239000012530 fluid Substances 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 238000010309 melting process Methods 0.000 claims description 3
- 238000011084 recovery Methods 0.000 claims 1
- 238000005516 engineering process Methods 0.000 abstract description 20
- 239000000428 dust Substances 0.000 abstract description 9
- 230000009467 reduction Effects 0.000 abstract description 8
- 239000004566 building material Substances 0.000 abstract 1
- 125000001309 chloro group Chemical class Cl* 0.000 abstract 1
- HGUFODBRKLSHSI-UHFFFAOYSA-N 2,3,7,8-tetrachloro-dibenzo-p-dioxin Chemical compound O1C2=CC(Cl)=C(Cl)C=C2OC2=C1C=C(Cl)C(Cl)=C2 HGUFODBRKLSHSI-UHFFFAOYSA-N 0.000 description 15
- 238000005265 energy consumption Methods 0.000 description 9
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 8
- 238000004056 waste incineration Methods 0.000 description 8
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- 230000006641 stabilisation Effects 0.000 description 6
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- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 5
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 2
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
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- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 150000003841 chloride salts Chemical class 0.000 description 2
- 150000001804 chlorine Chemical class 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 229910052801 chlorine Inorganic materials 0.000 description 2
- 229910001425 magnesium ion Inorganic materials 0.000 description 2
- 239000003002 pH adjusting agent Substances 0.000 description 2
- 239000002957 persistent organic pollutant Substances 0.000 description 2
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- 238000011010 flushing procedure Methods 0.000 description 1
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- 238000011160 research Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
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Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
- B09B5/00—Operations not covered by a single other subclass or by a single other group in this subclass
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D3/00—Halides of sodium, potassium or alkali metals in general
- C01D3/14—Purification
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C1/00—Ingredients generally applicable to manufacture of glasses, glazes, or vitreous enamels
- C03C1/002—Use of waste materials, e.g. slags
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention relates to a system and a method for treating fly ash by washing and desalting with water and combining high-temperature melting, wherein the system mainly comprises: the device comprises a fly ash elution unit, an eluent purification unit, a drying unit, an evaporation salt making unit and a high-temperature melting disposal unit, wherein an eluent outlet of the fly ash elution unit is connected with an inlet of the eluent purification unit, an outlet of the eluent purification unit is connected with an inlet of the evaporation salt making unit, an elution ash outlet of the fly ash elution unit is connected with the drying unit, and an outlet of the drying unit is connected with the high-temperature melting disposal unit. The method adopts a special multistage countercurrent rinsing technology to remove chlorine salt in the fly ash to prepare industrial salt; melting the eluted ash to prepare a vitreous building material; high-temperature flue gas is subjected to heat exchange and dust collection and then is discharged after reaching standards; the eluent is recycled after being treated, and zero emission is realized; the reduction, the resource utilization and the harmlessness of the fly ash treatment are realized.
Description
Technical Field
The invention belongs to the field of harmless treatment and resource utilization of hazardous wastes, and particularly relates to a system and a method for treating fly ash by water washing and desalination combined with high-temperature melting.
Background
Along with the development of economy and the improvement of the living standard of people, the garbage problem is increasingly prominent, and according to statistics, 2/3 in 668 cities in China are surrounded by garbage belts, namely 'garbage enclosing city'. The secondary pollution generated in the process of treating the garbage enables the 'garbage enclosure' to be evolved into 'dangerous waste enclosure', and the secondary pollution causes great harm to the living environment of people.
At present, the garbage disposal mode mainly comprises landfill and incineration. In terms of landfill, the garbage landfill not only occupies a large amount of land resources, but also can generate pollution harm to soil and underground water at any time like a bomb; although the reduction and resource treatment of the garbage are realized by the garbage incineration, a large amount of fly ash which is a toxic, harmful and difficultly-treated substance is still generated.
At present, fly ash is mainly treated by cement solidification or chemical stabilization, landfill and high-temperature stabilization. In terms of landfill, a large amount of land resources are required to be occupied, the long-term effect of the landfill has a large risk, and underground water and soil are easily polluted; with the increasing shortage of urban construction land and the increasing demand of ecological environment, the landfill treatment of waste incineration fly ash has been prohibited by various governments. The high-temperature stabilization treatment includes high-temperature sintering and high-temperature melting treatment, and the high-temperature stabilization treatment technology can remove harmful substances such as heavy metal, dioxin and the like in the fly ash at high temperature, and the slag can be used as materials for civil engineering, cement, buildings and the like. Therefore, the high-temperature stabilization treatment of fly ash has been a hot spot for research, application, and management, and has been widely used in developed countries such as the united states and germany.
Compared with European and American countries, the waste incineration fly ash in China has high content of soluble chloride salt, and the devices and pipelines which are easy to corrode are directly treated by high-temperature melting, so that the secondary fly ash generated by high-temperature melting is more difficult to treat. In view of the characteristic of high content of soluble chloride in fly ash in China, the fly ash needs to be pretreated for removing the soluble chloride before high-temperature stabilization treatment, so that the soluble chloride in the fly ash is removed.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a system and a method for washing and desalting fly ash and treating fly ash by high-temperature fusion, wherein the washing and desalting technology of fly ash is coupled with the treating technology of high-temperature fusion fly ash, so that the problems that the content of soluble chlorine salt in the fly ash from waste incineration in China is high, devices and pipelines which are easy to corrode are directly treated by high-temperature fusion, and secondary fly ash generated by high-temperature fusion is difficult to treat are solved.
In order to solve at least one of the above problems, the invention adopts the technical scheme that:
the system for treating fly ash by water washing and desalting combined high-temperature melting is characterized in that an eluent outlet of a fly ash eluting unit is connected with an inlet of an eluent purifying unit, an outlet of the eluent purifying unit is connected with an inlet of an evaporation salt-making unit, an eluting ash outlet of the fly ash eluting unit is connected with a drying unit, and an outlet of the drying unit is connected with a high-temperature melting treatment unit.
According to the embodiment of the invention, the fly ash elution unit comprises a mixer, a water washing reactor and an elution ash/liquid separator, wherein an inlet of the mixer is respectively connected with an outlet of a fly ash metering device and an outlet of a water distribution metering device, an outlet of the mixer is connected with the water washing reactor, an outlet of the water washing reactor is connected with an inlet of the elution ash/liquid separator, an elution ash outlet of the elution ash/liquid separator is connected with the drying unit, and an eluent outlet of the elution ash/liquid separator is connected with the eluent purification unit.
According to an embodiment of the present invention, the eluent purification unit includes a heavy metal removal reactor, a hardness removal reactor, a concentration and precipitation device, a precipitate removal device, a multi-stage filtration device, and a pH adjustment device, an inlet of the heavy metal removal reactor is connected to an eluent outlet of the elution ash/liquid separator, an outlet of the heavy metal removal reactor is connected to the hardness removal reactor, an outlet of the hardness removal reactor is connected to an inlet of the precipitate removal device, a precipitate outlet of the precipitate removal device is connected to the water washing reactor, an eluent outlet of the precipitate removal device is connected to an inlet of the concentration and precipitation device, an underflow outlet of the concentration and precipitation device is connected to the hardness removal reactor, and an overflow outlet of the concentration and precipitation device is connected to an inlet of the multi-stage filtration device, the outlet of the multistage filtering device is connected with the inlet of the pH adjusting device, and the outlet of the pH adjusting device is connected with the inlet of the evaporation salt making unit.
According to the embodiment of the invention, the evaporation salt production unit comprises a preheating heat exchanger, a steam compressor, a crystallization separator, a thickener, an enamel kettle, a potassium salt centrifuge, a potassium mother liquor tank, a potassium mother liquor heat exchanger, a sodium mother liquor tank, a sodium salt centrifuge, a forced circulation evaporator, a gas-liquid separator, a falling-film evaporator and a distilled water tank, wherein an outlet of an evaporation water supply tank is connected with the preheating heat exchanger, an outlet of the preheating heat exchanger is connected with the falling-film evaporator, outlets of the falling-film evaporator are respectively connected with the gas-liquid separator and the forced circulation evaporator, an outlet of the gas-liquid separator is connected with the steam compressor, an outlet of the steam compressor is respectively connected with the falling-film evaporator and the forced circulation evaporator, an outlet of the forced circulation evaporator is connected with an outlet of the crystallization separator, and outlets of the crystallization separator are respectively connected with the steam compressor, the vapor compressor, the distillation water tank and the evaporator, The thickener is connected with the sodium salt centrifugal machine and the enamel kettle respectively, an outlet of the sodium salt centrifugal machine is connected with the sodium mother liquor tank, an outlet of the enamel kettle is connected with the potassium salt centrifugal machine, the potassium salt centrifugal machine is connected with the potassium mother liquor tank, the potassium salt mother liquor tank is connected with the potassium mother liquor heat exchanger, and the forced circulation heat exchanger is connected with the sodium mother liquor tank and the potassium mother liquor heat exchanger respectively.
According to the embodiment of the invention, the drying unit comprises a water washing fly ash conveyor, a water washing fly ash feeder, a water washing fly ash dryer and a drying fly ash collector, wherein an outlet of the water washing fly ash conveyor is connected with an inlet of the water washing fly ash feeder, an outlet of the water washing fly ash feeder is connected with an inlet of the water washing fly ash dryer, an outlet of the water washing fly ash dryer is connected with an inlet of the drying fly ash collector, and an outlet of the drying fly ash collector is connected with the high-temperature melting disposal unit.
According to the embodiment of the invention, the high-temperature melting processing unit comprises a dry fly ash hoist, a furnace entering fly ash metering device, a melting furnace, a heat exchange device and a flue gas purification device, wherein an outlet of the dry fly ash hoist is connected with the furnace entering fly ash metering device, an outlet of the furnace entering fly ash metering device is connected with the melting furnace, high-temperature flue gas and a high-temperature fluid outlet of the high-temperature melting furnace are respectively connected with the heat exchange device, and a gas outlet of the heat exchange device is connected with the flue gas purification device.
Therefore, the system for the water washing desalination and high-temperature melting combined treatment of the fly ash disclosed by the embodiment of the invention has the advantages that the water washing dechlorination technology is coupled with the high-temperature melting technology, and a special multistage countercurrent rinsing technology is adopted, so that the dechlorination effect is good, the water consumption is low, and no dust is raised. The method of alkaline elution and heavy metal multiple capture is adopted, so that the heavy metal and dioxin in the fly ash are transferred less; the MVR evaporation salt making technology is adopted, salt is produced as a byproduct, condensed water is recycled, energy consumption is low, and pollution is avoided; the fly ash is dried by adopting the fused product and the waste heat of high-temperature flue gas, so that energy is saved and emission is reduced; the high-temperature melting fly ash is adopted, heavy metals and dioxin are thoroughly treated, the method is safe and environment-friendly, no after-troubles exist, and the reduction, the recycling and the harmlessness of the waste incineration fly ash treatment are completely realized.
In another aspect of the present invention, the present invention provides a method for water washing desalination of fly ash combined with high temperature melting disposal, which is performed by using the system for water washing desalination of fly ash combined with high temperature melting disposal according to an embodiment of the present invention, and according to a specific embodiment of the present invention, the method comprises:
(1) and (3) fly ash elution: desalting the fly ash, preparing fly ash slurry with the mass concentration of 20-30% by mixing the fly ash and the process water, and sequentially feeding the fly ash slurry into the water washing reactor and an elution ash/eluent separation device for carrying out fly ash water washing dechlorination treatment to obtain elution ash and eluent;
(2) purifying the eluent: purifying the eluent, namely adding an alkaline solution, a heavy metal remover and a hardness remover into the eluent in the step (1) for treatment, removing heavy metals in the eluent and reducing the hardness of the eluent, and then sequentially performing sand filtration, pH value adjustment and fine filtration to obtain purified eluent;
(3) evaporation salt preparation: sequentially carrying out preheating treatment, falling film evaporation treatment, forced circulation evaporation treatment and crystallization separation treatment on the purified eluent in the step (2) to obtain crystalline salt;
(4) and (3) drying: drying the elution ash in the step (1) by using the waste heat of the melting furnace to obtain dry ash, wherein the flue gas temperature in the drying process is 120-280 ℃;
(5) high-temperature melting: and (4) carrying out melting treatment on the dried ash in the step (4) to prepare a vitreous solid material.
Therefore, according to the method for the water washing desalination combined high-temperature melting treatment of the fly ash, which is disclosed by the embodiment of the invention, the water washing dechlorination technology and the high-temperature melting technology are coupled, and a special multistage countercurrent rinsing technology is adopted, so that the dechlorination effect is good, the water consumption is low, and no dust is raised. The method of alkaline elution and heavy metal multiple capture is adopted, so that the heavy metal and dioxin in the fly ash are transferred less; the MVR evaporation salt making technology is adopted, salt is produced as a byproduct, condensed water is recycled, energy consumption is low, and pollution is avoided; the fly ash is dried by adopting the fused product and the waste heat of high-temperature flue gas, so that energy is saved and emission is reduced; the high-temperature melting fly ash is adopted, heavy metals and dioxin are thoroughly treated, the method is safe and environment-friendly, no after-troubles exist, and the reduction, the recycling and the harmlessness of the waste incineration fly ash treatment are completely realized.
In some embodiments of the present invention, the method of fly ash water washing desalination combined with high temperature melting disposal further comprises: adding a flocculating agent into the elution ash/eluent in the step (1) in the separation process, wherein the fly ash elution process adopts multi-stage countercurrent elution, and the preferred number of elution stages is 2-4. Therefore, the method is beneficial to obtaining elution ash with the water content of lower than 40% and the elution liquid with the solid content of lower than 1%, and the removal rate of chloride ions in the fly ash is improved.
In some embodiments of the present invention, the method of fly ash water washing desalination combined with high temperature melting disposal further comprises: and (4) recovering waste heat in the high-temperature melting process from steam required in the step (3) and a drying heat source required in the step (4). Therefore, the residual heat of the melting furnace can be fully utilized.
In some embodiments of the present invention, the method of fly ash water washing desalination combined with high temperature melting disposal further comprises: the temperature range of the high-temperature melting of the fly ash in the step (5) is 1200-1800 ℃, and preferably 1300-1500 ℃. Therefore, the heavy metal in the fly ash can be solidified in the vitreous body by fully utilizing the high temperature of the melting furnace, and the dioxin is completely decomposed and is completely treated without aftereffect.
Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings.
FIG. 1 is a schematic diagram of a fly ash elution unit and an eluent purification unit for fly ash water washing desalination combined with high temperature melting treatment according to the present invention.
FIG. 2 is a schematic diagram of an evaporative salt production unit combining water washing and desalination of fly ash with high temperature melting treatment according to the present invention.
FIG. 3 is a schematic diagram of a drying unit and a melting furnace calcination unit in combination with a high temperature melting process for water washing and desalting of fly ash according to the present invention.
FIG. 4 is a schematic flow chart of the method of the present invention combining water washing and desalination of fly ash with high temperature melting disposal.
Wherein: a fly ash elution unit 100, a mixer 101, a water washing reactor 102, an elution ash/liquid separator 103, an elution liquid tank 104, an elution liquid purification unit 200, a heavy metal removal tank 201, a hardness removal reactor 202, a precipitate removal device 203, a concentration and precipitation device 204, a multi-stage filtration device 205, a Ph adjusting device 206, an evaporation salt making unit 300, a preheating heat exchanger 301, a vapor compressor 302, a crystallization separator 303, a thickener 304, an enamel kettle 305, a potassium salt centrifuge 306, a potassium mother liquid tank 307, a potassium mother liquid heat exchanger 308, a sodium mother liquid tank 309, a sodium salt centrifuge 310, a forced circulation evaporator 311, a gas-liquid separator 312, a falling film evaporator 313, a distilled water tank 314, a drying unit 400, a water washing fly ash conveyor 401, a water washing fly ash discharger 402, a water washing fly ash dryer 403, a drying fly ash collector 404, a drying elevator 405, a high-temperature melting disposal unit 500, a fly ash purification unit 200, a heavy metal removal tank 201, a hardness removal reactor 202, a precipitate removal device 203, a concentration and precipitation device 204, a potassium mother liquid tank 310, a potassium mother liquid separator 310, a high-liquid purification unit for purifying, a high-liquid purification unit for purifying liquid, a high-liquid purification unit for purifying liquid, a high-liquid purification unit for purifying liquid, a high-liquid purification unit for purifying liquid, a high-liquid purification unit for purifying liquid, a high-liquid purification unit for purifying liquid, a high-liquid purification unit for purifying liquid, a high-liquid purification unit for purifying liquid, a high-liquid purification unit for purifying liquid, a high-liquid purification unit for purifying liquid, a high-, A furnace entering fly ash metering device 501, a melting furnace 502 and a heat exchange device 503.
Detailed Description
In order that those skilled in the art will better understand the technical solutions of the present invention, the present invention will be further described in detail with reference to specific examples. The following examples are illustrative only and are not to be construed as limiting the invention. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications.
According to the embodiment of the invention, the waste incineration fly ash, kiln ash or secondary fly ash generated by high-temperature treatment can be used as raw materials for washing, desalting and high-temperature melting treatment.
In one aspect of the invention, the invention provides a system for water washing and desalting of fly ash combined with high-temperature melting treatment. According to an embodiment of the invention, the system comprises: an eluent outlet of the fly ash eluting unit is connected with an inlet of the eluent purifying unit, an outlet of the eluent purifying unit is connected with an inlet of the evaporation salt-making unit, an eluting ash outlet of the fly ash eluting unit is connected with the drying unit, and an outlet of the drying unit is connected with the high-temperature melting disposal unit; the fly ash elution unit comprises a mixer, a water washing reactor and an elution ash/liquid separator, wherein the inlet of the mixer is respectively connected with the outlet of a fly ash metering device and the outlet of a water distribution metering device, the outlet of the mixer is connected with the water washing reactor, the outlet of the water washing reactor is connected with the inlet of an elution ash/liquid separator, the elution ash outlet of the elution ash/liquid separator is connected with the drying unit, and the eluent outlet of the elution ash/liquid separator is connected with the eluent purification unit; the eluent purification unit comprises a heavy metal removal reactor, a hardness removal reactor, a concentration and precipitation device, a precipitate removal device, a multistage filtering device and a pH adjusting device, wherein an inlet of the heavy metal removal reactor is connected with an eluent outlet of the elution ash/liquid separator, an outlet of the heavy metal removal reactor is connected with the hardness removal reactor, an outlet of the hardness removal reactor is connected with an inlet of the precipitate removal device, a precipitate outlet of the precipitate removal device is connected with the water washing reactor, an eluent outlet of the precipitate removal device is connected with an inlet of the concentration and precipitation device, an underflow outlet of the concentration and precipitation device is connected with the hardness removal reactor, an overflow outlet of the concentration and precipitation device is connected with an inlet of the multistage filtering device, an outlet of the multistage filtering device is connected with an inlet of the pH adjusting device, the outlet of the pH adjusting device is connected with the inlet of the evaporation salt making unit; the evaporation salt-making unit comprises a preheating heat exchanger, a steam compressor, a crystallization separator, a thickener, an enamel kettle, a sylvite centrifuge, a sylvite mother liquor tank, a sylvite mother liquor heat exchanger, a sodium mother liquor tank, a sodium salt centrifuge, a forced circulation evaporator, a gas-liquid separator, a falling-film evaporator and a distilled water tank, wherein the outlet of an evaporation water supply tank is connected with the preheating heat exchanger, the outlet of the preheating heat exchanger is connected with the falling-film evaporator, the outlet of the falling-film evaporator is respectively connected with the gas-liquid separator and the forced circulation evaporator, the outlet of the gas-liquid separator is connected with the steam compressor, the outlet of the steam compressor is respectively connected with the falling-film evaporator and the forced circulation evaporator, the outlet of the forced circulation evaporator is connected with the outlet of the crystallization separator, and the outlet of the crystallization separator is respectively connected with the steam compressor, the potassium salt tank, the evaporator and the evaporator are respectively, The thickener is connected with the sodium salt centrifugal machine and the enamel kettle respectively, the outlet of the sodium salt centrifugal machine is connected with the sodium mother liquor tank, the outlet of the enamel kettle is connected with the potassium salt centrifugal machine, the potassium salt centrifugal machine is connected with the potassium mother liquor tank, the potassium salt mother liquor tank is connected with the potassium mother liquor heat exchanger, and the forced circulation heat exchanger is connected with the sodium mother liquor tank and the potassium mother liquor heat exchanger respectively; the drying unit comprises a washing fly ash conveyor, a washing fly ash feeder, a washing fly ash dryer and a drying fly ash collector, wherein the outlet of the washing fly ash conveyor is connected with the inlet of the washing fly ash feeder, the outlet of the washing fly ash feeder is connected with the inlet of the washing fly ash dryer, the outlet of the washing fly ash dryer is connected with the inlet of the drying fly ash collector, and the outlet of the drying fly ash collector is connected with the high-temperature melting disposal unit. The high-temperature melting disposal unit comprises a dry fly ash hoist, a furnace-entering fly ash metering device, a melting furnace, a heat exchange device and a flue gas purification device, wherein an outlet of the dry fly ash hoist is connected with the furnace-entering fly ash metering device, an outlet of the furnace-entering fly ash metering device is connected with the melting furnace, a high-temperature flue gas outlet and a high-temperature fluid outlet of the high-temperature melting furnace are respectively connected with the heat exchange device, and a gas outlet of the heat exchange device is connected with the flue gas purification device. The inventor finds that the water washing dechlorination technology is coupled with the high-temperature melting technology, and the special multi-stage countercurrent rinsing technology is adopted, so that the dechlorination effect is good, the water consumption is low, and no dust is generated. The method of alkaline elution and heavy metal multiple capture is adopted, so that the heavy metal and dioxin in the fly ash are transferred less; the MVR evaporation salt making technology is adopted, salt is produced as a byproduct, condensed water is recycled, energy consumption is low, and pollution is avoided; the fly ash is dried by adopting the fused product and the waste heat of high-temperature flue gas, so that energy is saved and emission is reduced; the high-temperature melting fly ash is adopted, heavy metals and dioxin are thoroughly treated, the method is safe and environment-friendly, no after-troubles exist, and the reduction, the recycling and the harmlessness of the waste incineration fly ash treatment are completely realized.
The system and reverse detailed description of the fly ash water washing desalination combined high temperature melting disposal of the present invention will be described with reference to FIGS. 1-3. According to an embodiment of the invention the system comprises: a fly ash elution unit 100, an eluent purification unit 200, an evaporation salt making unit 300, a drying unit 400 and a high temperature melting disposal unit 500.
According to the embodiment of the invention, the fly ash elution unit 100 comprises a mixer 101, a water washing reactor 102, an elution ash/liquid separator 103 and an elution liquid tank 104, wherein a fly ash inlet of the mixer 101 is respectively connected with a fly ash metering device outlet and a water distribution metering device outlet, an outlet of the mixer 101 is connected with the water washing reactor 102, an outlet of the water washing reactor 102 is connected with an inlet of the elution ash/liquid separator 103, an elution ash outlet of the elution ash/liquid separator 103 is connected with a drying unit 400, and an elution outlet of the elution ash/liquid separator 103 is connected with the elution liquid tank 104.
According to the embodiment of the invention, the first-stage to N-stage water washing can be adopted in the elution process according to the chlorine content requirements of the raw material and the water-washed fly ash, the water-washed slurry in each stage of water washing process is not limited to one-time ash/liquid separation, and the fly ash slurry can be subjected to 1-N times of separation processes according to the chlorine content requirements of the raw material and the water-washed fly ash. Another advantage of the present invention is that the fly ash elution process employs multi-stage counter-current rinsing, which significantly reduces water consumption in the fly ash elution process. The countercurrent rinsing in the invention means that when the first-stage, second-stage and … … N-stage are adopted for elution, the water washing liquid of the second stage is used as water for the first-stage water-washing fly ash pulping and distributing, the water washing liquid of the third stage is used as water for the second-stage water-washing fly ash pulping and distributing, … …, and the water washing liquid of the Nth stage is used as water for the Nth-1-stage water-washing fly ash pulping and distributing. It is noted that the skilled person can select the multi-stage rinsing and/or the multiple separation devices to be used according to the actual needs.
According to the embodiment of the invention, the fly ash elution process adopts multi-stage countercurrent rinsing, so that the water consumption in the elution process is greatly reduced, the dechlorination effect reaches more than 90 percent, and the problems of high water consumption and high content of chloride ions in the water-washed fly ash in the fly ash elution process are solved. The inventor finds that the water washing reactor and the elution ash/liquid separator in the fly ash elution process have no special requirements, and only the water washing fly ash with the water content of less than 40 percent and the water washing liquid with the solid content of less than 1 percent are obtained after the fly ash is eluted. In accordance with embodiments of the present invention, the inventors have discovered that plate and frame filter presses and centrifuges are presently preferred for the elution ash/liquid separator.
According to the embodiment of the present invention, the eluent purification unit 200 comprises a heavy metal removal tank 201, a hardness removal reactor 202, a precipitate removal device 203, a concentration and precipitation device 204, a multi-stage filtration device 205, and a Ph adjustment device 206, wherein an inlet of the heavy metal removal reactor 201 is connected with an eluent outlet of the elution ash/liquid separator 103, an outlet of the heavy metal removal reactor 201 is connected with the hardness removal reactor 202, an outlet of the hardness removal reactor 202 is connected with an inlet of the precipitate removal device 203, a precipitate outlet of the precipitate removal device 203 is connected with the water washing reactor 102, an eluent outlet of the precipitate removal device 203 is connected with an inlet of the concentration and precipitation device 204, a bottom flow outlet of the concentration and precipitation device 204 is connected with the hardness removal reactor 202, an overflow outlet of the concentration and precipitation device 204 is connected with an inlet of the multi-stage filtration device 205, an outlet of the multi-stage filtration device 205 is connected with an inlet of the Ph adjustment device 206, the outlet of the pH adjusting device 206 is connected to the inlet of the evaporative water supply tank.
According to the embodiment of the invention, according to the characteristics of the eluent and the requirement of the purified water quality, the heavy metal in the eluent is removed in multiple stages, so that the heavy metal in the eluent can be effectively removed; the filtration process of the eluent adopts multi-stage filtration, which is beneficial to effectively removing solid suspended matters in the eluent. According to the embodiment of the invention, through adopting multi-stage heavy metal removal, hardness removal and solid suspension filtration, impurities such as suspended matters, calcium and magnesium ions, heavy metals and the like in the washing liquid are removed after the washing liquid is subjected to physical and chemical purification treatment, so that the requirements of an evaporation salt-making process and the quality of crystallized salt are met.
According to the embodiment of the invention, the evaporation salt-making unit 300 comprises a preheating heat exchanger 301, a vapor compressor 302, a crystallization separator 303, a thickener 304, an enamel kettle 305, a potassium salt centrifuge 306, a potassium mother liquor tank 307, a potassium mother liquor heat exchanger 308, a sodium mother liquor tank 309, a sodium salt centrifuge 310, a forced circulation evaporator 311, a vapor-liquid separator 312, a falling-film evaporator 313 and a distilled water tank 314, wherein an outlet of the evaporation water supply tank is connected with the preheating heat exchanger 301, an outlet of the preheating heat exchanger 301 is connected with the falling-film evaporator 313, outlets of the falling-film evaporator 313 are respectively connected with the vapor-liquid separator 312 and the forced circulation evaporator 311, an outlet of the vapor-liquid separator 312 is connected with the vapor compressor 302, outlets of the vapor compressor 302 and the forced circulation evaporator 311 are respectively connected with the falling-film evaporator 312 and the forced circulation evaporator 311, an outlet of the forced circulation evaporator 311 is connected with an outlet of the crystallization separator 303, an outlet of the crystallization separator 303 is respectively connected with the vapor compressor 302, the thickener 304 and the evaporator 302, The thickener 304 is connected, the thickener 304 is respectively connected with a sodium salt centrifuge 310 and an enamel kettle 305, the outlet of the sodium salt centrifuge 310 is connected with a sodium mother liquor tank 309, the outlet of the enamel kettle 305 is connected with a potassium salt centrifuge 306, the potassium salt centrifuge 306 is connected with a potassium mother liquor tank 307, the potassium salt mother liquor tank 307 is connected with a potassium mother liquor heat exchanger 308, and the forced circulation heat exchanger 311 is respectively connected with the sodium mother liquor tank 309 and the potassium mother liquor heat exchanger 308.
According to the embodiment of the invention, whether salt separation is set or not can be determined according to engineering characteristics and the requirement of the quality of crystallized salt, and if salt separation is not performed, the enamel kettle 305, the potassium salt centrifuge 306, the potassium mother liquor tank 307, the potassium mother liquor heat exchanger 308 and the sodium mother liquor tank 309 can be omitted. In order to reduce energy consumption, evaporation condensate water heat exchange, non-condensation heat exchange and the like are generally adopted in the preheating heat exchange process, and heat energy in the evaporation process is fully utilized. And separating soluble salt and water in the water washing liquid by evaporation to obtain crystalline salt with the total amount of sodium chloride and potassium chloride not less than 90%, and recycling the evaporated condensate water.
According to the embodiment of the present invention, the drying unit 400 includes a washed fly ash conveyor 401, a washed fly ash discharger 402, a washed fly ash dryer 403, a dried fly ash collector 404, and a dried fly ash hoist 405, an outlet of the washed fly ash conveyor 401 is connected to an inlet of the washed fly ash discharger 402, an outlet of the washed fly ash discharger 402 is connected to an inlet of the washed fly ash dryer 403, an outlet of the washed fly ash dryer 403 is connected to an inlet of the dried fly ash collector 404, and an outlet of the dried fly ash collector 404 is connected to the dried fly ash hoist 405.
According to the embodiment of the invention, the fly ash drying process has no special requirements on drying equipment and dust collecting equipment, and only the moisture content of the washed fly ash is reduced through drying, so that the dried fly ash with the chloride ion content of less than 1% and the moisture content of less than 5% is obtained. The inventor finds that in order to meet the requirement of environmental protection, the inlet temperature of the hot drying air is required to be 300 ℃ in the drying process, preferably 180 ℃ in the drying process, pulse blowing is adopted in the ash removal mode of the dust collector, and the dust collector is required to meet the requirement that the concentration of the dust outlet is not higher than 10mg/m for carrying out the cultivation. In addition, the inventor also finds that a mixed drying measure is needed to avoid fly ash blockage, agglomeration and wall hanging in the drying and conveying processes, and fly ash special conveying equipment with functions of scattering, mixing and the like is adopted, so that the fly ash conveying effect is guaranteed, and the equipment and pipeline blockage is reduced.
According to the embodiment of the invention, the high-temperature melting disposal unit 500 comprises a furnace-entering fly ash metering device 501, a melting furnace 502 and a heat exchange device 503, wherein the furnace-entering fly ash metering device 501 is connected with an outlet of the dry fly ash hoist 405, an outlet of the furnace-entering fly ash metering device 501 is connected with the melting furnace 502, and an outlet of the melting furnace 502 is connected with the heat exchange device 503. The inventor finds that the melting furnace has no special requirement on the moisture of the fly ash entering the furnace, if the fly ash is not dried, the fly ash is sprayed into the furnace to meet the process requirement, only the high moisture content of the fly ash can increase the energy consumption of the melting furnace, and the energy consumption and carbon emission of the system ton fly ash of the melting furnace are reduced by drying the fly ash before entering the furnace.
The high-temperature environment of the melting furnace can thoroughly decompose organic pollutants such as dioxin and the like in the fly ash, and the burning rate of harmful components can reach more than 99.99 percent; the final product of the melting furnace is a vitreous solid material, which can effectively prevent heavy metals in the fly ash from dissolving out and avoid secondary pollution to the environment.
In another aspect of the invention, the invention provides a method for combining water washing and desalination of fly ash with high-temperature melting treatment. According to an embodiment of the present invention, the method is performed using the system of water washing desalination of fly ash combined with high temperature melting disposal described above. According to an embodiment of the invention, (1) fly ash elution: desalting the fly ash, preparing fly ash slurry with the mass concentration of 20-30% by mixing the fly ash and the process water, and sequentially feeding the fly ash slurry into the water washing reactor and an elution ash/eluent separation device for carrying out fly ash water washing dechlorination treatment to obtain elution ash and eluent; (2) purifying the eluent: purifying the eluent, namely adding an alkaline solution, a heavy metal remover and a hardness remover into the eluent in the step (1) for treatment, removing heavy metals in the eluent and reducing the hardness of the eluent, and then sequentially performing sand filtration, pH value adjustment and fine filtration to obtain purified eluent; (3) evaporation salt preparation: sequentially carrying out preheating treatment, falling film evaporation treatment, forced circulation evaporation treatment and crystallization separation treatment on the purified eluent in the step (2) to obtain crystalline salt; (4) and (3) drying: drying the elution ash in the step (1) by using the waste heat of the melting furnace to obtain dry ash, wherein the flue gas temperature in the drying process is 120-280 ℃; (5) high-temperature melting: and (4) carrying out melting treatment on the dried ash in the step (4) to prepare a vitreous solid material. Therefore, according to the invention, the water washing dechlorination technology is coupled with the high-temperature melting technology, and the special multi-stage countercurrent rinsing technology is adopted, so that the dechlorination effect is good, the water consumption is low, and no dust is raised. The method of alkaline elution and heavy metal multiple capture is adopted, so that the heavy metal and dioxin in the fly ash are transferred less; the MVR evaporation salt making technology is adopted, salt is produced as a byproduct, condensed water is recycled, energy consumption is low, and pollution is avoided; the fly ash is dried by adopting the fused product and the waste heat of high-temperature flue gas, so that energy is saved and emission is reduced; the high-temperature melting fly ash is adopted, heavy metals and dioxin are thoroughly treated, the method is safe and environment-friendly, no after-troubles exist, and the reduction, the recycling and the harmlessness of the waste incineration fly ash treatment are completely realized. It should be noted that the features and advantages described above for the system of washing and desalting fly ash and melting at high temperature are also applicable to the method of washing and desalting fly ash and melting at high temperature, and are not described herein again.
The method of the present invention for water washing desalination in combination with high temperature melting disposal of fly ash according to an embodiment of the present invention is described in detail below with reference to fig. 4, and comprises:
fly ash elution S100: washing fly ash with water, eluting ash/separating eluent
According to the embodiment of the invention, the fly ash and the process water are firstly prepared into fly ash slurry with the mass concentration of 20-30%, and the fly ash slurry is sequentially sent into the water washing reactor and the elution ash/eluent separation device for carrying out the water washing dechlorination treatment of the fly ash, so as to obtain elution ash and eluent. Thereby, the soluble chloride salt in the fly ash can be removed significantly.
The concentration of the fly ash slurry into which the fly ash and the process water are formulated is not particularly limited and can be selected as desired by those skilled in the art according to one embodiment of the present invention. According to the specific embodiment of the present invention, the number of rinsing times of the fly ash is not particularly limited, and those skilled in the art can determine according to actual conditions that the number of washing times varies according to the chloride ion content in the fly ash, and the higher the chloride ion content in the fly ash is, the more washing times are required. According to the embodiment of the invention, the characteristics of the countercurrent rinsing are not limited to the water washing liquid of the N grade as the pulp preparation water of the N-1 grade, and can be selected according to actual needs. According to the specific embodiment of the present invention, the elution times of the eluents in each stage of rinsing are not particularly limited, and may be selected from 1 to n times according to actual needs, and the times of different stages are not required to be consistent. According to the embodiment of the invention, the elution of fly ash after elution and the elution are not strictly limited, and in order to better meet the requirements of downstream units, a person skilled in the art usually requires that fly ash is washed and separated by counter current to remove soluble salts in fly ash, so as to obtain water-washed fly ash with the water content of less than 40% and water-washed liquid with the solid content of less than 1%.
Eluent purification S200: purifying the eluent
According to the embodiment of the invention, the eluent is firstly added with alkaline solution, heavy metal remover and hardness remover for treatment, heavy metal in the eluent is removed and the hardness of the eluent is reduced, and then sand filtration, pH value adjustment and fine filtration are sequentially carried out to obtain purified eluent. Therefore, the content of solid suspended matters, heavy metal ions and calcium and magnesium ions in the eluent is reduced, and the purification index of the eluent is improved.
According to an embodiment of the present invention, the inventors found that the order, kind and amount of the alkaline solution, the heavy metal removal agent and the hardness removal agent added to the eluent are not specifically limited, and can be determined by those skilled in the art according to actual conditions. The precipitate removing device according to the embodiment of the present invention is not particularly limited, and a centrifugal separation apparatus or a plate and frame separation apparatus is generally selected by those skilled in the art in consideration of technical maturity and use effect. According to the examples of the present invention, the inventors found that the number of filtration of the eluate is not significantly limited, and the order of the addition position of the pH adjusting agent and the filtration apparatus is not significantly limited, but the addition position of the pH adjusting agent needs to be after the precipitate removing device. According to the embodiment of the present invention, there is no strict limitation on the purification index of the eluent, and those skilled in the art generally require that the eluent is subjected to physicochemical purification treatment to meet the requirements of evaporation salt-making process and quality of crystallized salt.
Evaporation salt making S300: evaporating the purified eluent to produce salt
According to the embodiment of the invention, purified eluent is subjected to multi-stage evaporation to prepare crystalline salt, evaporated condensate water is used as process water or flushing water in a flying elution process and an eluent purification process, and the purified eluent is sequentially subjected to preheating treatment, falling film evaporation treatment, forced circulation evaporation treatment and crystallization separation treatment to obtain sodium salt and potassium salt. Therefore, the energy consumption in the evaporation process is reduced by adopting a steam mechanical recompression evaporation process.
According to an embodiment of the present invention, the inventors have found that the evaporation raw material can be preheated by utilizing the residual heat of the condensed water generated in the evaporation process, such as sensible heat of non-condensed water, latent heat of non-condensed water, and the like, and the steam or flue gas of the melting furnace can be used as the heat source in the preheating process. According to the embodiment of the invention, whether the salt separation is adopted in the evaporation salt making process is mainly determined by the requirements of the owner, and no clear limitation is made on whether the salt separation is adopted.
And (5) drying S400: drying the elution ash
According to the embodiment of the invention, the eluted ash is dried, and the mixed ash is dried by using the residual heat of the flue gas of the melting furnace to obtain the dried ash. Therefore, the problems of wall hanging, blockage and hardening in the process of conveying the eluted ash into the kiln are obviously reduced, the energy consumption of water evaporation in the process of calcining the fly ash in the melting furnace is reduced, and the carbon emission is reduced.
According to one embodiment of the present invention, the inventor finds that the heat source medium in the drying process has no obvious requirement, flue gas and steam can be selected, an indirect drying mode can be selected, the temperature of the heat source medium is not limited obviously, and in order to avoid the generation of toxic and harmful gas in the fly ash in the drying process, the temperature of the heat source is generally required to be below 300 ℃ by those skilled in the art.
High-temperature melting S500: high-temperature melting treatment is carried out on the dry fly ash
According to the embodiment of the invention, the dry fly ash is subjected to high-temperature melting treatment, organic pollutants such as dioxin in the fly ash can be thoroughly decomposed in the high-temperature environment of the melting furnace, the flue gas in the melting furnace is cooled rapidly in the region of 200-450 ℃, the re-synthesis of substances such as dioxin, bark and the like is reduced, the melting temperature of the fly ash in the melting furnace is high, and the incineration rate of harmful components can reach more than 99.99%. Therefore, the heavy metal can be solidified and the dioxin can be decomposed through melting, and the method is safe and has no aftereffect.
According to the embodiment of the invention, chlorine salt in the fly ash is extracted by water washing to prepare industrial salt, and the water-washed fly ash is treated at high temperature, so that dioxin is thoroughly decomposed and secondary synthesis conditions are not provided; the high-temperature flue gas is quickly cooled and dust-collected and then reaches the standard to be discharged; the eluent is recycled after being treated, and zero emission is realized. Completely realizes the harmlessness, reduction and reclamation of the fly ash treatment.
According to the scheme, the system and the method for the combined high-temperature melting treatment of the water washing and the desalination of the fly ash completely realize the reduction, the recycling and the harmless treatment of the fly ash.
In the present invention, unless otherwise expressly stated or limited, the terms "connected" and "connected" are to be construed broadly, e.g., as meaning either a fixed connection or a removable connection, or an integral part; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the description of the present invention, it is to be understood that the terms "upper", "lower", and the like, indicate orientations or positional relationships based on those shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described, it is understood that the embodiments are illustrative and not restrictive, that various changes, modifications, substitutions and alterations may be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. The system for treating fly ash by water washing and desalting combined high-temperature melting is characterized in that an eluent outlet of a fly ash eluting unit is connected with an inlet of an eluent purifying unit, an outlet of the eluent purifying unit is connected with an inlet of an evaporation salt making unit, an eluting ash outlet of the fly ash eluting unit is connected with a drying unit, and an outlet of the drying unit is connected with a high-temperature melting treatment unit.
2. The system according to claim 1, wherein the fly ash elution unit comprises a mixer, a water washing reactor and an elution ash/liquid separator, wherein an inlet of the mixer is respectively connected with an outlet of the fly ash metering device and an outlet of the water distribution metering device, an outlet of the mixer is connected with the water washing reactor, an outlet of the water washing reactor is connected with an inlet of the elution ash/liquid separator, an elution ash outlet of the elution ash/liquid separator is connected with the drying unit, and an elution outlet of the elution ash/liquid separator is connected with the elution liquid purification unit.
3. The system of claim 1, wherein the eluent purification unit comprises a heavy metal removal reactor, a hardness removal reactor, a concentration and precipitation device, a precipitate removal device, a multi-stage filtration device and a pH adjusting device, wherein an inlet of the heavy metal removal reactor is connected with an eluent outlet of the elution ash/liquid separator, an outlet of the heavy metal removal reactor is connected with the hardness removal reactor, an outlet of the hardness removal reactor is connected with an inlet of the precipitate removal device, a precipitate outlet of the precipitate removal device is connected with the water washing reactor, an eluent outlet of the precipitate removal device is connected with an inlet of the concentration and precipitation device, an underflow outlet of the concentration and precipitation device is connected with the hardness removal reactor, an overflow outlet of the concentration and precipitation device is connected with an inlet of the multi-stage filtration device, the outlet of the multistage filtering device is connected with the inlet of the pH adjusting device, and the outlet of the pH adjusting device is connected with the inlet of the evaporation salt making unit.
4. The system according to claim 1, wherein the evaporation salt production unit comprises a preheating heat exchanger, a steam compressor, a crystallization separator, a thickener, an enamel kettle, a potassium salt centrifuge, a potassium mother liquor tank, a potassium mother liquor heat exchanger, a sodium mother liquor tank, a sodium salt centrifuge, a forced circulation evaporator, a gas-liquid separator, a falling-film evaporator and a distilled water tank, an outlet of the evaporation water supply tank is connected with the preheating heat exchanger, an outlet of the preheating heat exchanger is connected with the falling-film evaporator, outlets of the falling-film evaporator are respectively connected with the gas-liquid separator and the forced circulation evaporator, an outlet of the gas-liquid separator is connected with the steam compressor, outlets of the steam compressor are respectively connected with the falling-film evaporator and the forced circulation evaporator, and an outlet of the forced circulation evaporator is connected with an outlet of the crystallization separator, the outlet of the crystallization separator is respectively connected with the steam compressor and the thickener, the thickener is respectively connected with the sodium salt centrifugal machine and the enamel kettle, the outlet of the sodium salt centrifugal machine is connected with the sodium mother liquor tank, the outlet of the enamel kettle is connected with the potassium salt centrifugal machine, the potassium salt centrifugal machine is connected with the potassium mother liquor tank, the potassium salt mother liquor tank is connected with the potassium mother liquor heat exchanger, and the forced circulation heat exchanger is respectively connected with the sodium mother liquor tank and the potassium mother liquor heat exchanger.
5. The system according to claim 1, wherein the drying unit comprises a water-washing fly ash conveyor, a water-washing fly ash discharger, a water-washing fly ash dryer and a drying fly ash collector, an outlet of the water-washing fly ash conveyor is connected with an inlet of the water-washing fly ash discharger, an outlet of the water-washing fly ash discharger is connected with an inlet of the water-washing fly ash dryer, an outlet of the water-washing fly ash dryer is connected with an inlet of the drying fly ash collector, and an outlet of the drying fly ash collector is connected with the high-temperature melting disposal unit.
6. The system of claim 1, wherein the high-temperature melting disposal unit comprises a dry fly ash hoist, a furnace-entering fly ash metering device, a melting furnace, a heat exchange device and a flue gas purification device, an outlet of the dry fly ash hoist is connected with the furnace-entering fly ash metering device, an outlet of the furnace-entering fly ash metering device is connected with the melting furnace, a high-temperature flue gas and a high-temperature fluid outlet of the high-temperature melting furnace are respectively connected with the heat exchange device, and a gas outlet of the heat exchange device is connected with the flue gas purification device.
7. A system for water washing desalination combined high temperature melting treatment of fly ash according to any one of claims 1-6, comprising a method for water washing desalination combined high temperature melting treatment of fly ash, characterized by comprising:
(1) and (3) fly ash elution: desalting the fly ash, preparing fly ash slurry with the mass concentration of 20-30% by mixing the fly ash and the process water, and sequentially feeding the fly ash slurry into the water washing reactor and an elution ash/eluent separation device for carrying out fly ash water washing dechlorination treatment to obtain elution ash and eluent;
(2) purifying the eluent: purifying the eluent, namely adding an alkaline solution, a heavy metal remover and a hardness remover into the eluent in the step (1) for treatment, removing heavy metals in the eluent and reducing the hardness of the eluent, and then sequentially performing sand filtration, pH value adjustment and fine filtration to obtain purified eluent;
(3) evaporation salt preparation: sequentially carrying out preheating treatment, falling film evaporation treatment, forced circulation evaporation treatment and crystallization separation treatment on the purified eluent in the step (2) to obtain crystalline salt;
(4) and (3) drying: drying the elution ash in the step (1) by using the waste heat of the melting furnace to obtain dry ash, wherein the flue gas temperature in the drying process is 120-280 ℃;
(5) high-temperature melting: and (4) carrying out melting treatment on the dried ash in the step (4) to prepare a vitreous solid material.
8. The method of claim 7, wherein the elution ash/eluent in step (1) is added with flocculant during separation, and the elution process of fly ash adopts multi-stage countercurrent elution, and the number of elution stages is preferably 2-4.
9. The method for water washing and desalting of fly ash combined with high temperature melting disposal according to claim 7, wherein the steam required in step (3) and the drying heat source required in step (4) are both from the waste heat recovery of the high temperature melting process.
10. The method for water desalination of fly ash combined with high temperature melting disposal according to claim 7, wherein the temperature range of the high temperature melting of fly ash in step (5) is 1200-1800 ℃, preferably 1300-1500 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010145815.4A CN113351612A (en) | 2020-03-05 | 2020-03-05 | System and method for treating fly ash by water washing and desalting combined with high-temperature melting |
Applications Claiming Priority (1)
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